A microprocessor based computer system for analysis of DNA molecules will be developed. This system will implement four basic functions: 1) semi-automatic acquisition of DNA sequence data from autoradiograms, 2) analysis and comparison of sequences and searches for homologies, 3) error free storage and transmission by telephone, disc or tape, of sequence data, including preparation of figures for publication, 4) integration of sequence data with data from electron microscopic restriction mapping studies. A major focus of our approach will be to permit the use of inexpensive "personal computers" now becoming widely available to achieve these objectives at low cost within the reach of many laboratories. We will demonstrate this system by application to the bacteriophage lambda DNA molecule.